Description: This recommended practice provides a set of guidelines that can be used by the operators of new start-up systems seeking guidance in developing manuals, methods, practices and procedures for the safe and effective maintenance of their Overhead Contact System (OCS), or by the maintenance organizations of existing well-established systems to amplify or refine their existing practices. This recommended practice provides general recommendations for performing maintenance work on dc OCS for transit systems. These recommendations are based on sound engineering principles, engineering safety considerations and field experience by many transit agencies. Included are technical explanations to cover certain testing of tools and equipment; field maintenance and care of tools and equipment; work methods for the maintenance of the OCS; and recommended safety practices and procedures for persons working in the vicinity of energized lines.